1. Field of the Invention
The present invention relates to a semiconductor light-emitting device including a semiconductor chip having a pair of electrode films in the same side of a mounting plate, to a method of manufacturing the same, and to a mounting plate used for the method thereof.
2. Description of the Related Art
In recent years, semiconductor light-emitting devices including a semiconductor laser device in which a nitride semiconductor such as GaN is employed as a light source for short-wavelength light have been developed. Generally, with the semiconductor laser device utilizing the nitride semiconductor, an n-type layer, an active layer and a p-type layer, which are made of the nitride semiconductor are stacked in sequence on a substrate made of sapphire (Al2O3). Among a pair of electrode films of the semiconductor laser device, a p-side electrode is formed on the p-type layer which is the most upper layer in the semiconductor layer, while an n-type electrode is formed on the n-type layer which is exposed by etching the p-type layer and the active layer. Hence, the substrate, the semiconductor layer, the p-side electrode and the n-side electrode are collectively called a semiconductor chip.
In the semiconductor light-emitting device, the semiconductor chip is mounted on a mounting plate called a submount. The semiconductor chip is mounted on the mounting plate in a state, in which a side of the semiconductor layer is opposed to the mounting plate in order to scatter heat generated in the semiconductor layer effectively. The mounting plate has a pair of lead electrode layers formed in a side where the semiconductor chip is mounted thereon, and a solder film is formed on the lead layers. After mounting the semiconductor chip on the mounting plate, the p-side and the n-side electrodes of the semiconductor chip respectively contact with a pair of the lead electrode layers via the solder film.
However, in the conventional semiconductor light-emitting device, when the semiconductor chip is worn on the submount, the pressed solder film with the p-side and the n-side electrodes of the semiconductor chip is squeezed out to the side of the solder layer. Then, the squeezed-out solder may adhere to a pn junction part of the semiconductor chip, which causes the short circuit failure.
Additionally, the squeezed-out solder may adhere to a vicinity of an ejection part of a laser beam. In such a case, a shape of the laser beam changes, and what's worse, an optical-power output decreases. If a shape of the laser beam changes as mentioned before, specifically, when this semiconductor light-emitting device is applied to an optical disk apparatus and so on, it leads to less tracking accuracy. On top of that, such decrease of the optical-power output of the laser beam causes increase of heating value, because a large amount of current must be flowed to the semiconductor chip in order to acquire rated output.